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A186272 The sum of the Fibonacci and shifted tribonacci sequences. 0
1, 1, 2, 3, 4, 8, 13, 22, 38, 65, 112, 194, 337, 588, 1030, 1811, 3196, 5660, 10057, 17926, 32046, 57445, 103236, 185962, 335697, 607184, 1100186, 1996699, 3629044, 6604536, 12033861, 21949630, 40073798, 73225249, 133902408, 245023146, 448626225, 821848892, 1506270798 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Limit ratio is 1.839286755214161 ...

Last digit sequence has a period of 1860, starting from 3rd element.

LINKS

Table of n, a(n) for n=1..39.

Index entries for linear recurrences with constant coefficients, signature (2,1,-1,-2,-1).

FORMULA

a(n) = A000045(n-1) + A000213(n-3).

G.f.: x+x^2 -x^3*(1+x)*(x^2+3*x-2) / ( (x^2+x-1)*(x^3+x^2+x-1) ). - R. J. Mathar, Feb 16 2011

EXAMPLE

a(10) = 65 = Fib(9) + Trib(7) = 34 + 31.

MATHEMATICA

Rest[CoefficientList[Series[x+x^2-x^3(1+x)(x^2+3*x-2)/((x^2+x-1)(x^3+x^2+x-1)), {x, 0, 50}], x]]  (* Harvey P. Dale, Feb 24 2011 *)

CROSSREFS

Cf. A000045, A000213.

Sequence in context: A219968 A126042 A076227 * A092075 A091415 A166342

Adjacent sequences:  A186269 A186270 A186271 * A186273 A186274 A186275

KEYWORD

nonn

AUTHOR

Carmine Suriano, Feb 16 2011

STATUS

approved

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Last modified September 19 11:23 EDT 2021. Contains 347556 sequences. (Running on oeis4.)